The technique of nanofiltration lies between ultrafiltration and reverse osmosis. However, nanofiltration is a low cost process and is capable of removing pesticides, organic matter, desalination of sea water, oil process and pollutants from industrial waste water. The separation mechanism can be attributed to dielectric, sieving and Donnan effect. Charged nanofiltration membrane attracts opposite charges to pass through it and repels like charges on the basis of difference in dielectric constant. The main challenge in implementation of nanofiltration membrane is its propensity towards fouling and low performance at high temperature. The membrane fouling is a critical problem for efficient commercialization of nanofiltration. Nanoparticles based membranes can be developed by assembling engineered nanoparticles into porous membranes or blending them with polymeric or inorganic membranes.
Most of the research in the field of nanoscience is dedicated to the development of different synthesis routes to nanoparticles and nanostructures. These efforts gave access to nanomaterials with a wide range of compositions, monodisperse crystallite size, unprecedented crystallite shapes and with complex assembly properties. TiO2 nanostructures have a wide range of applications due to their optical and catalytic properties which depend on the crystalline state (anatase, rutile or brookite). Due to strong oxidizing power, high stability, high chemical inertness and having low cost of titanium dioxide semiconductor make it a promising material for photocatalytic applications. Among all, anatase phase exhibits most metastable and photocatalytic properties. Calcination temperature render the material to a single crystalline phase. Anatase phase is present if calcination is carried out at 400° C. 51.46% while calcination at 600° C. only rutile phase is obtained. Tin oxide (SnO2), a transparent conducting oxide (TCO) has a tetragonal rutile structure, with a bandgap of 3.6 eV. Unloaded SnO2 has the property of low electrical resistance and high optical transparency in visible range of electromagnetic spectrum. It has applications in solar cell, light emitting diodes, transparent electromagnetic shielding material.
RE (rare earth)-doped (Gd, Sm, Eu etc) nano-materials may play an important role in fabricating devices like optical, telecommunication, solid-state lasers, and many others. Therefore, the development of a facile synthetic method toward high quality RE-doped nanomaterial with uniform size and shape appears to having key importance for exploration of new research and application fields. RE-doped nanoparticles have been suggested as a promising new class of material, in comparison with organic dyes and semiconductor quantum dots and show superior chemical and optical properties.
The purpose of this invention is to prepare tin oxide-titania (SnO2—TiO2) nanoparticles in the presence of three different solvents (Ethyl acetate, Benzyl alcohol, Ethylene glycol) as directing medium, through sol-gel followed by hydrothermal method. Study of the effect of different solvents on base material SnO2—TiO2 was carried out by keeping all other factors constant. Lanthanum metal was doped on the base material SnO2—TiO2. The relation between particle size and band gap of La/SnO2—TiO2 was investigated. Photocatalytic activity was studied with the degradation of Methylene Blue. Photocatalytic applications of La/SnO2—TiO2 prepared in the presence of three solvents was compared. The effect of varying dielectric constant of solvents on band gap and photocatalytic activity was also studied in the nanofiltration system.